// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_CHILD_MEMORY_CHILD_MEMORY_COORDINATOR_IMPL_H_
#define CONTENT_CHILD_MEMORY_CHILD_MEMORY_COORDINATOR_IMPL_H_

#include "base/compiler_specific.h"
#include "base/memory/memory_coordinator_client.h"
#include "content/common/child_memory_coordinator.mojom.h"
#include "content/common/content_export.h"
#include "content/common/memory_coordinator.mojom.h"
#include "mojo/public/cpp/bindings/binding.h"

namespace content {

class CONTENT_EXPORT ChildMemoryCoordinatorDelegate {
public:
    virtual ~ChildMemoryCoordinatorDelegate() { }

    // Called when the system requests immediate actions to free memory.
    virtual void OnTrimMemoryImmediately() = 0;
};

// ChildMemoryCoordinatorImpl is the implementation of ChildMemoryCoordinator.
// It lives in child processes and is responsible for dispatching memory events
// to its clients.
class CONTENT_EXPORT ChildMemoryCoordinatorImpl
    : NON_EXPORTED_BASE(public mojom::ChildMemoryCoordinator) {
public:
    // Returns the instance of ChildMemoryCoordinatorImpl. Could be nullptr.
    static ChildMemoryCoordinatorImpl* GetInstance();

    ChildMemoryCoordinatorImpl(mojom::MemoryCoordinatorHandlePtr parent,
        ChildMemoryCoordinatorDelegate* delegate);
    ~ChildMemoryCoordinatorImpl() override;

    // mojom::ChildMemoryCoordinator implementations:
    void OnStateChange(mojom::MemoryState state) override;

protected:
    ChildMemoryCoordinatorDelegate* delegate() { return delegate_; }

private:
    friend class ChildMemoryCoordinatorImplTest;

    mojo::Binding<mojom::ChildMemoryCoordinator> binding_;
    mojom::MemoryCoordinatorHandlePtr parent_;
    ChildMemoryCoordinatorDelegate* delegate_;

    DISALLOW_COPY_AND_ASSIGN(ChildMemoryCoordinatorImpl);
};

// Factory function for creating a ChildMemoryCoordinator for the current
// platform. Doesn't take the ownership of |delegate|.
CONTENT_EXPORT std::unique_ptr<ChildMemoryCoordinatorImpl>
CreateChildMemoryCoordinator(mojom::MemoryCoordinatorHandlePtr parent,
    ChildMemoryCoordinatorDelegate* delegate);

} // namespace content

#endif // CONTENT_CHILD_MEMORY_CHILD_MEMORY_COORDINATOR_IMPL_H_
